1. Field of the Invention
The present invention relates to an LED lamp unit.
2. Description of the Related Art
Conventionally, as an LED lamp, a lamp type and an SMD (surface mount device) type have been known. In case where these LED lamps are used as vehicle lamps, for example, an LED lamp unit has been constructed by soldering leads of the LED lamp to a printed board, and then, embedding the printed board into a case part, and the LED lamp unit thus constructed has been mounted to a determined position of the vehicle. The printed board has been arranged in an illumination control device in the vehicle, whereby flashing and lightness of the LED when the LED is lighted up have been controlled by switches and control circuits in the vehicle.
In the conventional LED lamp unit as described above, the printed board on which the LED lamp is mounted has been formed of resin, and therefore, in some cases, radiation of heat from the LED lamp or heat at the time of mounting has been insufficient. In order to solve the problem, the applicant of the invention has proposed in the prior patent application (JP-A-2003-258314) such a structure of an LED lamp unit that the circuit section is formed of a metal plate, whereby effective heat radiation has been achieved to enhance reliability, and at the same time, the LED lamp unit has been less influenced by the heat on occasion of mounting the LED lamp, thereby to realize high manufacturing yield.
Also, JP-A-H11-103096 and JP-A-2000-216442 exists as related art.
In the LED lamp unit disclosed in JP-A-2003-258314, an LED lamp, a resistor element, a diode and so on are connected to a same plane of the metal plate which constitutes the circuit section. In such a structure, spaces for respective components, and connecting regions of the respective components on the metal plate must be secured on the same plane, and hence, it is difficult to make the unit compact. Under the circumstance, the invention makes it a main problem to provide an LED lamp unit of a type that a circuit section is formed of a metal plate, which can be made more compact in structure.